The security module of a mobile or portable telephone is known under the designation “SIM card” (Subscriber Identity Module) that constitutes the central security element of these telephones. The telephony operator introduces, during manufacturing and/or during a personalization step, a number called IMSI (International Mobile Subscriber Identification) that serves to identify in a secure and unique way each subscriber desiring to connect to a mobile network. Each mobile phone, hereinafter called mobile equipment, is physically identified by a number stored in a non-volatile memory of the mobile equipment. This number, called IMEI, (International Mobile Equipment Identifier) contains an identification of the type of mobile equipment and a serial number serving to identify in a unique way a given mobile equipment on a network of the type of GSM (Global System for Mobile Communications), GPRS (General Packet Radio System) or UMTS (Universal Mobile Telecommunications System). Moreover, a mobile equipment is characterized by a software version SVN (Software Version Number) indicating the updating state of the software system installed on the mobile equipment. The combination of the identification of the type and serial number of the mobile equipment with the software version (SVN) gives a new identification, called IMEISV (International Mobile Equipment Identifier and Software Version Number). The same identification concept is also applied to WLAN (Wireless LAN) or bidirectional cable TV. The physical identifier can be a MAC (Media Access Control) address that corresponds to the unique address identifying the hardware configuration of a user's equipment on an IP (Internet Protocol) network and the software version can be transmitted by upper layer protocols based on IP.
The ETSI (“European Telecommunications Standards Institute”) standards define a mobile station (MS, mobile station) composed of a mobile equipment (ME, mobile equipment) and a subscriber module (SIM, Subscriber Identity Module). This subscriber module is usually removable, that is to say that it can be withdrawn or transferred from one mobile equipment to another.
During the commissioning of a mobile equipment, more particularly at the time of its connection to an operator network, information comprising the identification data is exchanged between the mobile equipment and the management center of the operator that authorizes or prohibits its use. At present, a mobile equipment offers to the user, in addition to its usual function of establishing telephone conversations by means of access to a mobile network, the use of numerous other supplementary value added services such as the consultation of different data, remote banking transactions, electronic trade, accessing multimedia contents, etc. These improved services require an ever-increasing level of security in order to protect users against possible frauds caused by third parties attempting to exploit security failures that may appear on mobile equipment.
A verification becomes thus necessary on at least two levels: on the one hand at the level of the mobile equipment itself and on the other hand at the level of software applications allowing the functioning of the different services proposed by the operator or third parties. These applications are usually downloaded from the server of an application supplier, which involves the necessity of verifying this downloading. It is thus a question of guaranteeing that the subscriber module only provides data to authorized applications once this module has been recognized by the control server as being able to function with the mobile equipment into which it is inserted.
The subscribed module can contain confidential information such as a bank account number or a password. An application working on the mobile equipment will be in charge to use of this personal data in order to supply the awaited service. Nevertheless, an application could divert this personal data for other usage than the dialogue with the concerned application supplier. This could in result an important tort for the owner of the subscriber module.
These applications executed in the mobile equipment use resources available in the subscriber module. Resources are understood to mean different functions and data necessary for the correct function of an application. Certain resources can be common to several applications, in particular the functions linked to security. The subscribed module can in this way block or alter the working of certain applications for which the security conditions established by the operator and/or application suppliers are not respected in the mobile equipment in question or the rights of the user of the mobile equipment are insufficient.
The document FR2831362 describes a secured transaction process between a mobile phone provided with a SIM card and an applications server. The aim of this process is to protect the rights linked to the use of applications downloaded from the server by means of the SIM card.
According to this process, a trusted connection is first established between the server and the SIM card by means of the secured exchange of public keys, then the purchase of an application is carried out through the transmission of a request file by the mobile equipment to the server. The latter partially or entirely encrypts the application and transmits to the mobile equipment a cryptogram formed by the encryption key and a command, the whole encrypted with a public key known by the SIM card. On reception by the mobile equipment, this cryptogram is decrypted and the key is stored in the SIM card. The execution of the command leads to the downloading in the mobile equipment of the application that is partially or entirely encrypted by the server. Once downloaded, the application is decrypted by the key stored in the SIM card and is then installed in the mobile equipment.
According to this process, the using rights of the application in the mobile equipment are protected because of the trusted link initially established between the equipment and the server and preceding the transaction. The role played by the server is focused rather on the rights management or DRM (Digital Rights Management) of the users of an application in a mobile equipment. The solution developed hereinafter is oriented rather towards the management of risks (Risk Management) taken into account by the operator, the application supplier or the user in relation to an application.